Successive approach of medium optimization using one-factor-at-a-time and response surface methodology for improved β-mannanase production from Streptomyces sp.

β-Mannanase is an enzyme catalyzing the β-1,4-mannosidic linkages of the hemi-cellulolytic structure. Optimization of medium components was studied for β-mannanase production from Streptomyces sp. RDA1496 using One-Factor-At-a-Time and resulting activity was found to be 244.54 IU/mL. Subsequently, Plackett-Burman (PB) design was adopted to evaluate the effect of guar gum, coprameal, peptone, yeast extract, fructose, inoculum size, NaCl, K2HPO4, KH2PO4 and CaCl2. Analysis of variance revealed the correlation coefficient (R2) of 0.9996 for the performed model at a significant level (p < 0.05). Four significant variables were optimized using central composite design of response surface methodology (RSM) at five different coded levels. The optimum concentration of significant factors namely fructose, guar gum, peptone, and K2HPO4 were found to be 4.81 g/L, 7.09 g/L, 4.91 g/L, and 2.05 g/L respectively. PB and RSM-guided experimental design, resulted in maximum β-mannanase production of 415.96 IU/mL, which is 5.55-fold increase from un-optimized condition.